Power unit of the pressure fluid type



June 2, 1953 s. BQM LEOD POWER UNIT OF THE PRESSURE FLUID TYPE 2 Sheets-Sheet 1 Filed April 16, 1951 INVENTOR.

JEWART B. MC LEOD 6 ATTO R N YS June 2, 19 s. B. MQLEOD POWER UNIT 0? THE PRESSURETLUID TYPE 1 Filed April 16, 1951 *2 SheetS-Sheei 2 INVENTOR.

STEWART B.MCLEOD syfl FIG.4.

ATTORN YS Patented June 2, 1953 UNITED STATES PATENT" OFFICE Stewart B. McLeod, Dearborn, Mich., assignor to Detroit Harvester Company, Detroit, Mich., a corporation of Michigan v Application April 16, 1951; Serial No. 221,272. 7 Claims. (01. 103-41) The present invention relates to a power unit and, more particularly to a power unit comprising an electric motor, a pump, a reservoir, and a power cylinder, all connected to a supporting body to provide a self-contained compact source of hydraulic power. The power unit is capable of many applications but is particularly useful in conjunction with automotive vehicles. The electric motor may conveniently be operated off the'electric system of the vehicle and the unit permits the development of hydraulic power for various purposes, such for example as raising and lowering windows and convertible tops, and causing longitudinal adjustment of the front seat of the vehicle.

It is an object of the present invention to provide a power unit of the character described capable of being used in a variety of positions, so that a single unit with or without minor changes in attachments, may be, employed to perform any of the foregoing functions or other functions as desired.

More specifically, it is an object of the present invention to provide a power unit of the character described provided with a reservoir designed to receive a relief flow of hydraulic fluid upon operation of the unit in one direction and to restore such fluid to the power system upon operation of the unit in the other direction, in which the reservoir is so designed as to be operable for the purposes stated when the power unit is in any one of a variety of different posi-v tions.

More specifically, it is an object of the presentinvention to provide a; body for supporting a motor, pump and power cylinder, said body having ;a reservoir cavity therein, a hollow or cuplike closure'for the cavity designed to cooperate therewith to provide an enlarged reservoir, and conduit means in communication with the reservoir having a port located substantially midway between two opposite sides of the reservoir. Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a longitudinal vertical section through the unit.

. Figure 2, is a bottom plan view ofthe unit illustrated in Figure 1. I I Figure 3 is a section on the line 3-3, Figure 1. Figure 4 is a vertical section through a modified construction.

Referring now to Figures 1-3 the unit com-' prises a main supporting base or body It preferably in the form of a casting. While of irregular form the body J0 is generally an elongated flat body provided with certainrecesses;

, pinion [6. The recess [4 and motor seat I2 are interconnected by-abore 20 to. permit the attachment of the shaft 22 driven by motor 24, to theupinion I6. in driving relation thereto. A removable closure plate 26 is provided for thepumprecess andis detachably secured thereto by suitable bolts 28.

At the same side of the body ID as the motor seat I2 but at the opposite end thereof is a cylinder seat indicated generally at 30 and comprising an annular outwardly projecting wall 32. The cylinder seat 30 is adapted to constitute one end closure for ascylinder 34 which is supported on the wall 32 and retained in sealing relation thereonby a removable ring 36. Located within the cylinder 34 is a piston 38 to which is connected a. piston rod 40 which extends through the opposite end wall 42 of the cylinder and is adaptedto be connected to .a part to be actuated by the unit. I

The body II) has a-cavity 44 adapted to form arreservoir45 when closediby a removable cup like or hollow closure 46 which will presently be described in detail. The cavity 44 and the interior of the closure 46 together constitute the reservoir .45 for hydraulic fluid.

It will beappreciated that as the piston 38 moves longitudinally of the cylinder 34, a different amount of fluid is displaced from the cylinder than is introduced into the cylinder. In other word's, as the piston 38 moves-upwardly as seen at its ends than intermediate the ends thereof, as well indicated in dotted lines in Figure 2. The closure 46 is downwardly open and of cupshape so as to supplement the reservoir capacity as well illustrated in Figure 1. The closure 4%, whose cross-section is best seen in Figure 3, is similar to that of thecavity 44,-is however of less cross-sectional area than the cavity. The side of the closure 46 as indicated at 4B, is concavely curved to conform to the outer cylindrical surface of the motor 24. Moreover, it will be observed that the elongated closure 46 is disposed intermediate the motor 24 and the cylinder 34 in a manner to conserve space. The --"closure 46 'is provided with an opening in its top wall through which the reservoir may be filled and the opening is provided with a removable closure plug 49.

The body I is provided with arcuate ports 50 and 52 which communicate with the pump recess H4. The body is provided with-a first passage 54 communicating with the port 511 and communicating'also with a vertical passage 56 which'opens into the bottom of the cylinder seat 30. The outer end of the passage 54 is sealed by a closure plug 58. The port 52 communicates with a .pas sage 6i whichextends longitudinally of the body ill-and is provided at its-outerend with a. fitting 62 to which is connected ametal -pipe 64. The upper end of the-pipe54-carriesafitting fifi which communicates with the upper end closure 42 of cylinder 34. A transverse drilled :passage 68 is provided which communicates with passages 54!.

and 68 and intermedi-ate its ends the passage 58 communicates with a "short vertically extending passage H3. Extending upwardly from the-.passage l0 and partly supported therein-isa conduit 12 for apurpose which will presently'appear. It may be mentioned at this time that'the conduit 12 in general is responsible for-the ability "to use the power unit in a :plurality of different .iIJOSitions.

The-transverse passage S8 is 'closed at its l outer ends by'removable plugs 'M and 16 andis fo'rmed with an intermediate restricted portionzproviding valve seats with which ball valves 18 and 80 cooperate. Intermediate the ball valves 18 and '86 is a rigid elongated abutment'e1ement 82 'which is of such lengththat onlyone of the ball valves 18 or 80 may beseated atone time.

Thebody ID at the side thereof opposite to the motor and'cylinder seats, ancl i'n alignment with the axis of the cylinder seat Bmis provided with,

.a pair of mounting cars 84. It willbe'observed that the body [0 may thus be mounted for rocking movement during use aboutan axis =whi'ch extends perpendicular to the axis of the piston rod 49.

The motor 24 is of the reversible'type, and the pump composed of thepump elements t6 and H is reversible sothat pump ports 58 and 52 may operate as inlet or discharge ports depending upon the direction of rotation of the motor. With the piston 38 in its lowermostposition as illustrated in Figure 1, the motor-may be rotated.

in a direction to discharge hydraulic :fluid through the port 56 whence it will flow through the passage 54 to the vertical passage 56, and thence into the bottom of the cylinder 34, thus raising thelpiston. At this time, pressure in the passage establishes pressureonthe ball valve 18 and seats the valve on itsseat thus preventhis flow o ffluidfroin the passage: 54 to the reservoi'r. Upward movement of the ipiston 38 force's hydraulic fluidb'ut of the top of the cylinder'through the'conduit F4 and thence into the i passage 69 in the body H2. Due to the fact that more fluid flows into the bottom of the cylinder 34 than is forced out of its upper end, the fluid returned to the passage 60 through the conduit 54 is insufficient to supply the needs of the pump. Since the ball valve 78 is atthis time "on its seat the ball valve '80 is forced'off of its seat by the elongated rigid element 32 and fluid from the reservoir will therefore flow through conduit 72 into the transverse passage 58 and thence outwardly into the passage '56 whence it is returned to. the

inlet side of the pump.

With the piston moving downward in the cylinder, conditions are reversed and the pump port 52 becomes the outlet port. At this: time fluid under pressure flows through the passage 60, through the fitting 62, conduit 64, fitting E6 and into the upper end of the cylinder 34. Pressure in the passage SE1 retains the valve 80 on its valve sea-tend prevents flow of fluid fromxpassage '60 into the reservoir 45. Under these operating conditions, downward movement of the piston displaces a greater quantity of fluid from -the underside 'of the piston than :is introduced iti't'o the upper side. Accordingly, more fluid is forced out of thepa ssage 55 into the passage 54 than c'an be accommodated. by the pump. However, at this time the ball valve 78 is retained 'ofi it's seait due to pressure on ball valve 8B and the action of the rigid element 82. Thus the excess hum forced into the passage 54 is at this time forced I does'not require'the presence'of th'e vertically e'irtending conduit -12. However,"the conduit 12 is provided so that the unit maybe operated in=the position shown in Figure l, 'or may be operated when in-verted or on its side. The provision-of the enlarged cup-like closure for the reservoir permits the reservoir to be filled to a level as "indicated by the numeral mi, which 'as seenin-Figure 1, is substantially above'th'e port 92 constituted by the upper open end of the conduit I2. It will be recalled that the cross-sectional-shape of the reservoir, and particularly the closure lii, is as indicate in Figure 3 so "that a substantial volume of iiuid is thus retained above -the port 92, particularly when it is recalled that the-end portions of the reservoir are substantially wider than the restricted central portion. Moreover, the cavity l i in the body l ii is of greater crosssectional area than the "interior space Within the closure 46. Therefore, if the unit is inverted the level'of hydraulic fiuidwill shift tow-ard and be yond the port 92 so that the conduit 12 will in such case extend down into the body of hydraulic fluid in the reservoir. The reservoir'wilrnormak ly be filled =to-an extent such that if the unit turned on either side'the level'of hydraulic fiuid will extend substantially above the position of the-port 92 provided by the open endof theconduit 72. Thus, it will bea-pparentthatthe'unit illustrated in Figure 1 =mayibeoperatedin the-position shown, in a position inverted with respect thereto, or in a position resulting from turning the unit' ilover in either dii'ection aboiit the lo'hgitudinal axis of the body 15. Moreoven 'the-reservoir may be 'operated in such :position that the motor-24 directly underlies the-cylinder 34.

Referring now to Figure 4, thei'e is illustrated a construction designed for use with a cylinder requiring a shorter stroke. Since the construction illustrated in Figure 4 is generally identical 55:; with that illustrated .injFigure 11 only .such features as involve differences .will beidescribed in detail. The cylinder I34 in Figure 4 is of substantially less stroke than the cylinder 34 in Figure 1, and accordinglya smaller volumetriccapacity for the, reservoir, M5 is satisfactory. Therefore, the removable closure I46 may be of substantially less height than the closure 46 illustrated in Figure 1..

Also, thevertical conduit l'l2'may be correspondingly shorter than thev conduit 12 illustrated in Figure 1. Accordingly,.it is possibleto provide identical castings or b'odiesil 0 which are supplied with identical motors and pumps. In the event that a longer workingstroke is. required a longer cylinder is mounted on the cylinder seat and an enlarged reservoir forming closure 46 is provided. In the event that a shorter working stroke is satisfactory, a shorter cylinder I34 is substituted, and the shorter reservoir forming closure M6 is employed. The relatively long conduit (2 is of course employed with the enlarged closure 46, whereas the relatively short conduit I12 is employed with the relatively small closure M6. Conduits l2 and H2 are inserted in enlarged portions of the vertical bore and may be readily exchanged.

Of course the exact valve arrangement may be modified or supplemented depending upon the use of the cylinder and whether the cylinder is to perform a locking function as well as a power moving function.

Accordingly, the present construction permits the most economical manufacture of power units, since the most expensive and critical parts thereof are standard for units intended for widely different purposes. Moreover, by providing the reservoir extension in the removable closure for the reservoir cavity in the body, and by providing a conduit connected to the hydraulic fluid system and having a port located generally centrally of the reservoir, the unit may be employed in a wide variety of different positions.

In connection with the location of the inlet ports 92 and I92, it will be observed that in either arrangement the port is located substantially midway between the top and bottom of the reservoir 45 when the reservoir is in the position illustrated. Moreover, it is located substantially midway between the ends of the reservoir which are adjacent the edges of the body Hi. In more general terms, it may be said that the ports 92 and 92 are located substantially midway between at least two pairs of opposite reservoir defining walls.

The drawings and the foregoing specification constitute a description of the improved power unit in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. A power unit comprising a generally flat body having a pump recess at one side adjacent one end thereof, a motor seat at the other side of said body in alignment with said pump recess, a cylinder seat at the same side of said body as said motor seat, a reservoir cavity in said body open at the side thereof provided with said seats, said reservoir cavity extending generally transversely of said body intermediate said seats, a closure for said reservoir cavity cooperating therewith to form an enlarged reservoir, said closure being in the form of a cup having a cross-section similar to the cross-section of said cavity and extending outwardly of said bodyintermediate said seats, and passages including passages in-said body connecting'saidpump recess,:said reservoir cavity, and said cylinder seat.

2. A unit as defined in claim 1 comprising a conduit connecting said reservoir to said passages and opening into said reservoir substantially within the narrow central portion of said reservoir, and substantially midway between the bottom of said cavity and the top of said closure. 1

3. A power unit comprising a body havingat one side thereof a pump recess, rotary pump mechanism in said pump recess, amotor seat at the opposite side of said body from said pump re cessfa motor-on said motor-seat connected to said pump mechanism, a cylinder seat on said body at the same side as said motor seat, a cylin der having an inner end mounted on said cylinder seat, a reservoir within said body, a removable closure for said reservoir intermediate said motor and cylinder, said closure being hollow and forming an enlargement of said reservoir, a first flow passage in said body connecting said pump recess to the inner end of said cylinder, a second flow passage in said body and an external conduit connecting said pump recess to the outer end of said cylinder, relief and supply passages connecting said reservoir with both of said flow passages, valves controlling flow through said passages, said relief and supply passages comprising a common port located within said hollow closure.

4. A power unit comp-rising a body having at one side thereof a pump recess, rotary pump mechanism in said pump recess, a motor seat at the opposite side of said body from said pump recess, a motor on said motor seat connected to said pump mechanism, a cylinder seat on said body at the same side as said motor seat, a cylinder having an inner end mounted on said cylinder seat, a reservoir within said body, a removable closure for said reservoir intermediate said motor and cylinder, said closure being hollow and forming an enlargement of said reservoir, a first flow passage in said body connecting said pump recess to the inner end of said cylinder, a second flow passage in said body and an external conduit connecting said pump recess to the outer end of said cylinder, relief and supply passages connecting said reservoir with both of said flow passages, valves controlling fiow through said passages, a conduit connected at one end to said relief and supply passages and open at its other end within said reservoir at a point located substantially midway between the bottom of said reservoir and the top of said closure.

5. A power unit comprising a body having at one side thereof a pump recess, rotary pump mechanism in said pump recess, a motor seat at the opposite side of said body from said pump recess, a motor on said motor seat connected to said pump mechanism, a cylinder seat on said body at the same side as said motor seat, a cylinder having an inner end mounted on said cylinder seat, a reservoir within said body, a removable closure for said reservoir intermediate said motor and cylinder, said closure being hollow and forming an enlargement of said reservoir, and extending outwardly of said body into the space between said motor and said cylinder, a first flow passage in said body connecting said pump recess to the inner end of said cylinder, a second flow passage in said body and an external conduit connecting said pump recess to the outer end of said cylinder, relief and supply passages connecting amaaee said reservoir with both 'of said flow :passages, va'lves controlling tiiow through said passages, said relief and supply passages having a :common port within said reservoir substantially midway between the bottom of said reservoir and the top of said :olosure.

6. 'Sizucture as defined in claim 5 in which one side :of said closureis'concavelycnrved to conform to one adjacent surface of said motor :and cylinder.

'7. vStructure as defined in claim 5, said reservoir-having enlarged endlobes and an intermediate narrow portion substantially on the center line'of said motor and cylinder, a closure for said reservoir having an interior cavity of similar 8 crossseetionand extending outward of-said body alongside saidmotor.

V STEWART B. MCLEOD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,078,127 Coleman Nov. 11, 1913 1,812,585 Ellis June 30, 1931 2,143,546 Day Jan. 10, 1939 2,257,245 Rudolph Sept. 30, 1941 "2,322,314 Pomeroy June 22, 1943 2,324,635 Meyer July 20, 1943 2,388,755 McLeod Nov. 13, 1945 

